This project is directed toward the detection of functional changes in the cardiovascular system associated with compounds of environmental significance to which toxicologically significant exposure would be expected by inhalation. Allylamine has been reported to produce myocardial necrosis in experimental animals. We have given rabbits allylamine in the drinking water in concentrations less than those reported to produce myocardial necrosis detectable by light microscopy. Myocardial function subsequently assessed in vitro indicates that measurable functional impairment may precede the appearance of frank, structural damage. A possible sparing effect of concurrent treatment of rabbits with allylamine and aminoguanidine is under investigation.